1. Field of the Invention
This invention relates to an apparatus for growing cells or tissue culture in vitro and more particularly comprises a new and improved cell culture insert for supporting tissue cultures in a fluid medium containing nutrients which promote the tissue culture growth.
2. Description of the Related Art
Cell culture inserts comprise a plastic material with a membrane on the bottom surface thereof so that there is free diffusion and transport of ions and macro-molecules. With the use of a suspended microporous membrane, two cell types, for example, can be cultured, one on each side of the membrane in the same well. Without suspension, cells on the bottom surface of the membrane would be exposed to damage. The microporous membrane allows free passage of macromolecules, proteins and ions. As a result, the interactions of the two cell types can be studied without actual physical contact between the two cell populations in the suspended state of the insert.
Conventional cell culture inserts and devices are described in U.S. Pat. Nos. 4,871,674 and 5,026,649. U.S. Pat. No. 4,871,674 discloses a culture cell which comprises discontinuous projecting parts for hanging the culture cell provided on an upper circumferential part and a membrane filter on the bottom. U.S. Pat. No. 5,026,649 discloses a culture cell which comprises a projecting part for hanging the culture cell which is provided over the whole upper circumferential part, with openings in the sidewall for exchanging gas and for pipeting sample.
In the use of these cell culture inserts, gases may not be exchanged sufficiently because the area of the openings is small. Furthermore, as described in U.S. Pat. No. 5,026,649, portions of the cell culture inserts could possibly become contaminated because the openings are provided in the sidewall of the cell culture insert.